On Tue, Jul 29, 2014 at 06:28:29PM +0000, Xie, Wei wrote:
> >> There are also various extensions to Postfix to handle SPF and SRS.
>
> Would you please talk a little more about above topic?
Postfix neither has nor should have any built-in feature to add
"Resent-From:", it is not only the wrong header to use, but the
modification is recipient dependent, and messages can have multiple
recipients, so such modifications are only possible at delivery
time, when the envelope is "split" to one recipient per transaction.
Forwarding via virtual(5) aliases happens on input, before the
envelope is split for delivery, and cannot and does not modify
message content. Forwarding to a single recipient at a time, via
a delivery agent like local(8) can modify the message content
(headers). Currently, a "Delivered-To" header is added. One might
add features to add more headers (ideally not misuse Resent-From).
You can create a pipe(8) or similar delivery agent or even an SMTP
proxy filter configured for single-recipient concurrency that
performs the relevant content modifications.
--
Viktor.
